docs: def _get_col_dimstr(tdim, is_string=False):
      """
      not for variable length
      """
      dimstr = ''
      if tdim is None:
          dimstr = 'array[bad TDIM]'
      else:
          if is_string:
              if len(tdim) > 1:
                  dimstr = [str(d) for d in tdim[1:]]
          else:
              if len(tdim) > 1 or tdim[0] > 1:
                  dimstr = [str(d) for d in tdim]
          if dimstr != '':
              dimstr = ','.join(dimstr)
              dimstr = 'array[%s]' % dimstr
  
      return dimstr